Diesel Place banner

1 - 20 of 24 Posts

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #1
2 summers ago towing 35' travel trailer north thru Louisiana 107 degrees went into limp. 0087, changed fuel filter. Truck always ran hotter than I liked, so changed fan clutch at destination in Michigan. Heading south back to Florida in mountains limp. Now have obd2, got going again faster. Studied booster pumps, went with single no extra filters Kennedy pump. Didn't install yet. Last summer, towed same trailer on secondary roads flater lands cooler temp to Michigan. No problem. Installed pump. I think description said I would feel better throttle response and performance, I did not. Before this all started I fixed and reinstalled a gravity feed saddle tank 15 gal metal, welded mounting strap tares. Thought maybe I plugged pickup screen. Winter trip to Michigan no trailer. Bought a sump that fits a 3" hole sawed in tank bottem, also added a ball valve and a vac motion 50 micron in line screen with o ring for diesel. I now have that throttle response and performance. Wife says she can feel it. Next trailer trip to Michigan this summer.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #2
Last summer towing back to Florida after pump install limp in mountain obd2 saved day.
 

·
Registered
Joined
·
12,740 Posts
clean the cooling stack [a/c,rad,tranny,intercooler] outside fins,,


then look at replacing the rubber fuel lines near the eng-trans,where the make the 90deg turns [they get soft] and collapse
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #4
I removed stack cover this morning. Inspected and garden hose jetted what I could get at. What I could see was reasonable clean to me. I looked at fuel lines at firewall just above steering shaft. Two sizes I expect smaller is a return. They had a ribbed tube over them like a factory fix for external collapse. Do they just collapse internally? Wouldn't booster pump solve this somewhat?
 

·
Registered
Joined
·
2,566 Posts
A lift pump solves (or covers up) many small problems inthe fueling system. I think that ALL Duramax diesels should be running a lift pump. Try it, you'll like it.
 
  • Like
Reactions: IGO1320

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #6
Found igo 1320. new cure for p0087. It's 20 pages.looks like a good final fix.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #7
Well I am not to the final cure yet. July from Florida to Michigan. In Georgia on secondary roads towing started setting 87 code multiple times. Stopped using cruise control, started manually downshifting to keep rpms up going up grades. Would lug down before it would downshift and go limp. Kept obd plugged in and reset on the fly.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #8
Decided to shim the pressure relief valve. Bought shim kit. Was confident in myself also bought solid block plug. Watched videos. Added 2 shims. Towed in Michigan, so far no code. Outside temp. Cooler than in July that may be a factor. More towing to Florida. Today replace alternator and left front wheel bearing.
 

·
Registered
Joined
·
3,587 Posts
Well I am not to the final cure yet. July from Florida to Michigan. In Georgia on secondary roads towing started setting 87 code multiple times. Stopped using cruise control, started manually downshifting to keep rpms up going up grades. Would lug down before it would downshift and go limp. Kept obd plugged in and reset on the fly.
You added a dual fueler and still have a P0087? Do you have a lift pump?
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #10
I read what you did, I think it's a logical cure.i am not ready to invest in the duel fueler yet. Getting closer. I have a single Kennedy pump.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #11
Well made trip from Michigan to Florida towing our 35 " travel trailer. Kentucky south on 231 and I65 mostly. When temp got above 81 started having 87 issues. Tried restring trans. To 5th. That helped some. 1/4 tank to almost full didn't seem to make much difference, to me it's thinking tank fuel temp. Had it 87 three times in 10 minutes. Air temp got over 90. Seemed to do it more. Last day in Florida to homosassa flat land towing 66 no code set. With shimming high pressure relief valve trans and motor worked together better. I keep obd tool plugged in and set for two enter pushes and easily kept going. 20 to 30 times of day resetting gets old and nerving. Decision time. Right now looks like ppe duel fueler time.probably install next April .
 

·
Registered
Joined
·
11 Posts
Howdy all,

New to the forum and I appreciate all that I've been learning from Y'all.

Bowebow have you rebuilt or replaced your fuel filter head? As the O-rings get old in there air can be introduced causing your symptoms.

As I've just posted on another forum the same advise I feel like the poster child for this recommendation!

Good luck
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #13
kalimax thank you for the suggestion. I will give new head a try.
 

·
Vendor
Joined
·
9,676 Posts
I read what you did, I think it's a logical cure.i am not ready to invest in the duel fueler yet. Getting closer. I have a single Kennedy pump.

For problem trucks I recommend the twin pump setup. Don't bother with the filter head it is under pressure from the lift pump.



Day in day out I am doing ECM programming and lift pumps for these situations. Initial skepticism is soon replaced with euphoria as teh truck wil run like it never has before.

Reading:
http://www.kennedydiesel.com/docs/Duramax LBZ and LMM P0087 Low Fuel Pressure code.pdf
 
  • Like
Reactions: ShopSpecialties

·
Registered
Joined
·
49 Posts
I looked at fuel lines at firewall just above steering shaft. Two sizes I expect smaller is a return. They had a ribbed tube over them like a factory fix for external collapse. Do they just collapse internally? Wouldn't booster pump solve this somewhat?
This is where I found another collapsed line (shop found the first one by the tranny)...collapsed at the crimped fitting AND at the quik-connect.
Replaced it with 7/16" hose and double clamps.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #16
Mr Kennedy. I have your single lift pump. Will that stop possible hose colapse? The hoses have a ribbed plastic over them looks like its making them stay round and open. Is this a factory fix? will a single lift pump pump thru the second filter that you offer? I have read more on your ecm program upgrade. Can a second cp3 pump (duel fueler) be added later without reprograming?
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #17
up date. I had health issues most of 2019, didnt tow any where, 2 surgery's. bought a new trailer this year 1000# less possible weight. towed to michigan from florida, lots of p0087 codes , 30 times 1 day, adjusted driving style 5 th gear limit, no cruise. went to Drury diesel, he put his kennedy gauge on, vac. 7.5. I have a lift pump, wasnt working, last checked at filter change apr. 2018. thinking it quit on trip in may 2018 because of problems and fixes I tried that didnt do anything. had to find what happened to pump. weather connection at pump fell apart when I disconnected it. eliminated connection with crimp fittings. 2.4 psi with truck running same as day of filter change. 3.3 psi not running. 3.5 vac. running, no pump. gave info to diesel shop, suggested loaded tow trip. trip with trailer, in drive, with cruse on, 90 miles, up grades, full petal acceleration, no p0087 problems. drove back, in 4wd by accident, lol, no problem. 7/14/20.
installed aux cooler to return line. because problem came on more above 85 degrees. replaced fuel hose next to transmission and top left engine by firewall, the trans hose looked like it would flatten under suction. hoses at filter were changed in 2019, no differance.
so no dual fueler. using single kennedy pump.
time will tell.
with 3.5 vac maybe new valley pump in future.?
need a 85 degree+ day to tow.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #18
taking drive today. obd2, autel al319, on. no trailer. 20,000#+ getting on freeway. 26120+ full throttle. much higher pump pressures and more responsive pressure changes. finally something that's made a difference. truck feels like it got all 360hp and650 torque available after4 yrs. now instead of pump changes thinking of better filtration like I should have been thinking 4 yrs ago. I like the thought of Kennedy's mega filter that mounts after the stock filter to the air box mount. probably should rebuild filter head also . I have a off brand 1 for back up , will keep that for emergency I guess.
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #19
note to self. check pressures with kennedy gauge more often! also dont get sick
 

·
Registered
2007 classic gmc cc
Joined
·
38 Posts
Discussion Starter #20
7/18/20. 1 battery was 4.2v when second battery wasnt hooked up. agm batteries die different than other batteries and not in a good way. I wonder if that would affect the electronics of the truck? starts happier, will see if it operates better now. I know when they both go bad truck goes crazy and shuts down.
 
1 - 20 of 24 Posts
Top